Process for the production of vinyl acetate

Abstract

A process for the fluid bed production of vinyl acetate which comprises reacting ethylene, acetic acid and an oxygen-containing gas in a fluid bed reactor at elevated temperature in the presence of a fluidised bed of catalyst, in which process, catalyst is added to said fluidised bed of catalyst, wherein the overall catalytic activity of the fluidised bed of catalyst is controlled to a pre-determined value by adjusting the activity and/or adjusting the rate of addition of said added catalyst.

I claim:  
     
       1. A process for the fluid bed production of vinyl acetate which comprises reacting ethylene, acetic acid and an oxygen-containing gas in a fluid bed reactor at elevated temperature in the presence of a fluidised bed of catalyst, in which process, catalyst is added to said fluidised bed of catalyst, wherein the overall catalytic activity of the fluidised bed of catalyst is controlled to a pre-determined value by adjusting the activity of said added catalyst and/or adjusting the rate of addition of said added catalyst. 
     
     
       2. A process as claimed in  claim 1  in which the added catalyst has a different activity than the initial activity of the catalyst in the fluidised bed. 
     
     
       3. A process as claimed in  claim 2  in which the added catalyst has a higher activity than the initial activity of the catalyst in the fluidised bed. 
     
     
       4. A process as claimed in  claim 3  in which the added catalyst has a higher active metal loading than the catalyst in the fluidised bed. 
     
     
       5. A process as claimed in  claim 2  in which the added catalyst has a lower activity than the initial activity of the catalyst in the fluidised bed. 
     
     
       6. A process as claimed in  claim 5  in which the added catalyst has a lower active metal loading than the catalyst in the fluidised bed. 
     
     
       7. A process as claimed in  claim 5  in which the added catalyst is diluted with inert support material. 
     
     
       8. A process as claimed in  claim 1  in which the overall catalytic activity of the fluidised bed of catalyst is controlled to a pre-determined value by increasing the rate of addition of said added catalyst. 
     
     
       9. A process as claimed in  claim 8  which further comprises decreasing the rate of removal of catalyst from the fluidised bed. 
     
     
       10. A process as claimed in  claim 1  in which the overall catalytic activity of the fluidised bed of catalyst is controlled to a pre-determined value by decreasing the rate of addition of said added catalyst. 
     
     
       11. A process as claimed in  claim 10  which further comprises increasing the rate of removal of catalyst from the fluidised bed. 
     
     
       12. A process for the fluid bed production of vinyl acetate which comprises reacting ethylene, acetic acid and an oxygen-containing gas in a fluid bed reactor at elevated temperature in the presence of a fluidised bed of catalyst, in which process, catalyst is added to said fluidised bed of catalyst, wherein the overall production rate of the process is adjusted to a pre-determined value by adjusting the activity of said added catalyst and optionally adjusting the rate of addition of said added catalyst. 
     
     
       13. A process as claimed in  claim 12  in which the added catalyst has a different activity than the initial activity of the catalyst in the fluidised bed. 
     
     
       14. A process as claimed in  claim 13  in which the added catalyst has a higher activity than the initial activity of the catalyst in the fluidised bed. 
     
     
       15. A process as claimed in  claim 14  in which the added catalyst has a higher active metal loading than the catalyst in the fluidised bed. 
     
     
       16. A process as claimed in  claim 13  in which the added catalyst has a lower activity than the initial activity of the catalyst in the fluidised bed. 
     
     
       17. A process as claimed in  claim 16  in which the added catalyst has a lower active metal loading than the catalyst in the fluidised bed. 
     
     
       18. A process as claimed in  claim 16  in which the added catalyst is diluted with inert support material.